1. Field of the Invention
The present invention relates to a surface treatment agent used in hydrophobization treatment of a substrate surface, and a surface treatment method using the same.
2. Related Art
In the production of semiconductor devices and the like, a lithography technique is applied when forming an inorganic pattern on a substrate. With this lithography technique, a photosensitive resin composition is used to provide a photosensitive resin layer on a substrate, then actinic radiation is selectively irradiated (exposed) to this, and a resin pattern (resist pattern) is formed on the substrate by performing a developing process. Then, an inorganic pattern is formed by etching the substrate with this resin pattern as a mask.
However, in recent years, trends in higher integration and miniaturization of semiconductor devices have grown, and thus progress towards miniaturization and higher aspect ratios of the inorganic patterns has advanced. However, a problem has arisen of so-called pattern collapse in the meantime. This pattern collapse is a phenomenon when forming several inorganic patterns on a substrate in parallel, in which adjacent patterns close in so as to lean on one another, and depending on the situation, the pattern becomes damaged and separate from the base. If such pattern collapse occurs, the desired product will not be obtained, thereby causing a decline in the yield and reliability of the product.
This pattern collapse is known to occur when drying a rinse liquid in a rinsing process after pattern formation, due to the surface tension of this rinse liquid. In fact, when the rinse liquid is removed in a drying step, stress based on the surface tension of the rinse liquid acts between patterns, whereby pattern collapse occurs.
Consequently, despite there having been numerous experiments thus far to prevent pattern collapse by adding a substance (isopropanol, fluorine-based surfactants, etc.) to the rinse liquid that causes the surface tension to decrease (e.g., refer to Patent Documents 1 and 2), the prevention of pattern collapse has been insufficient with the schemes of such rinse liquids.    Patent Document 1: Japanese Unexamined Patent Application, Publication No. H6-163391    Patent Document 2: Japanese Unexamined Patent Application, Publication No. H7-142349    Patent Document 3: Japanese Translation of PCT International Publication, Publication No. H11-511900    Patent Document 4: Japanese Unexamined Patent Application, Publication No. 2011-122137